Radioactive components of scales at the inner surface of pipes in oilfields of Kazakhstan

Summary

This report presents the results of the determination of radionuclide component of the scales on the inner surfaces of oil well pipes and pump-compressors for certain oilfields in Kazakhstan. Results of 96 investigations show that the main contamination of pipe surface scales with radionuclides was related to the accumulation of ²²⁶Ra, ²²⁸Ra and their daughter decay products. Study of the scales removed by means of a special solution of “COX ASIA-CLEAN' revealed that practically all radionuclides were removed from the inner surface of the pipes. Scales, after segregation from the solution, contained the radionuclides in strongly bound conditions. Loss of radon isotopes comprised at most 3% to 5% of the radioactivity within the scales. These results suggest that an economically effective method for burial of radioactive scales is possible. Methods of cleaning and burial were tested at one of the oilfields in Kazakhstan.